Table 5 Variables and their levels used for the CCD experiment for incubation time, pH, peptone, glucose, ferric chloride and calcium chloride
Levels | |||||
|---|---|---|---|---|---|
Variables | − 2 | − 1 | 0 | + 1 | + 2 |
X1 (PH) | 2.5 | 3 | 7 | 11 | 14 |
X2 (incubation time) | 3 | 7 | 14 | 14 | 22 |
X3 (peptone) | 5 | 5.3 | 12.5 | 20 | 30.3 |
X4 (glucose) | 5 | 5.3 | 12.5 | 20 | 30.3 |
X5 (calcium chloride) | 0.1 | 0.4 | 0.6 | 0.8 | 1 |
X16 (ferric chloride) | 0.1 | 0.4 | 0.6 | 0.8 | 1 |